1. Field of the Invention
This invention is related in general to the field of data storage systems. In particular, the invention consists of a system for managing computer support systems.
2. Description of the Prior Art
In FIG. 1, a computer storage system 10 includes host servers (“hosts”) 12, data processing servers 14, a data storage system 16, and various support systems 18 such as power supplies 18a, batteries 18b, fans 18c, and temperature sensors 18d. Each data processing server 14 may include a plurality of processing devices grouped into a processing cluster (“cluster”) 20 and may be substantially identical and redundant. Imposed upon the physical components of the computer storage system 10 may be a multitude of virtualized storage servers referred to as images 22 as shown in FIG. 2. Each image 22 typically resides on two or more clusters. In the event of a cluster failure, however, an image 22 can failover to the remaining clusters.
The support systems 18 are hardware devices that provide services other than data storage. Each image 22 typically has access to and can use these devices. Additionally, these support devices 18 may have the ability to generate reports related to events, faults, and failures. However, only one image 22 should own each support system 18, i.e., be responsible for accepting these reports, for responding to the events, faults, and failures, and for managing these support systems. The owning image is referred to as the master image. However, each image may access the services of the support systems. Accordingly, it would be desirable to have a system for establishing ownership over a support system 18 while allowing other images to access the support system.
One approach is to provide a separate set of support systems 18 for each hardware image. However, this approach is extremely expensive as multiple devices are necessary and each may be dramatically underutilized. Therefore, it is desirable to have a system for establishing ownership over a support system 18 that is efficient and economical.
Another approach is to utilize a static multi-tiered architecture that allows one image to own the hardware while other images access the devices through the owning image via image-to-image communication. However, a problem occurs if the image 22 tasked with managing the support systems 18 fails, precluding use of the support systems 18 by the other viable images. Accordingly, it is desirable to have a system for dynamically establishing ownership over support systems 18.
In a traditional dynamic system, a system user can establish a master image. Subsequently, if the master image fails or is taken off-line, the system user can establish a different master image. However, this approach requires active intervention on the part of a system user. If the system user is not immediately available, the support systems 18 will go unmanaged and all images may be precluded from accessing the support systems. Therefore, it is desirable to have a dynamic system for establishing a master image that does not require active intervention by a system user.
A predetermined hierarchy of dynamic ownership allows ownership to pass from one image to another without intervention by a system user. A default profile may be established including a primary master image with associated secondary master images. However, this profile must be modified each time a hierarchy of images changes. Accordingly, it is desirable to have a system of dynamic ownership that is itself established dynamically.
In U.S. Pat. No. 5,553,287, Bailey et al. disclose a computer system for switchably connecting an input/output (“I/O”) device to a host via a channel subsystem in connection with means for dynamically managing I/O connectivity. Bailey's invention includes a centralized control lock associated with hardware resources. However, no resources are provided for identifying which image is responsible for managing each hardware resource. It is desirable to have a master lock that identifies the owning image.
In U.S. patent application 2003/0120743 A1, Coatney et al. disclose a system for implementing ownership including writing ownership information to a predetermined area of a device. However, no provision has been made to ensure that a master image remains viable. In other words, if a master image assumes ownership over a support system 18 and then fails, the support system may be unaware of the failure of the master image. Normally, this situation would require that a new master image be selected through image-to-image communication. This requires that the images be aware of each other. However, it is sometimes desirable to have independent systems on common hardware, precluding the use of image-to-image communication. Accordingly, it is desirable to have a system for establishing a master image that does not require image-to-image communication, is scalable, and does not require system user intervention, failover profiles, or significant downtime.